[World Trigger] The cool thing about this series: even arcs in which the main characters are absent wind up being relevant to them in the end.

It's quite refreshing after reading, say, Bleach and Naruto, where you lose track of the main characters for years at a time and the fights going on in the meantime have nothing to do with them.

Also, the current arc which just ended lasted for fifteen chapters. And involved 33 characters on the good side.

33 characters*